I thought the ending was true to Carrie's manic nature. She sacrificed any chance of relationship with her daughter and family, and continued to do what she excels at and gives her a sense of purpose. At the same time, she will constantly live on the edge because she has to maintain a double life balance. This 24/7 act is the only type of existence under which Carrie can live without Brody and Franny.
I thought it was brilliant! In general, it was well written, with consistent lines of character and level of quality, credible and satisfactory, without being mushy on the one hand or maddening on the other. If there were any weaknesses, I would say that there was nothing personal addressed during the season, especially in relation to the daughter. Furthermore, although I like that Carrie has replaced the Russian asset and that ties her to Saul, I think that, ultimately, she is unlikely to be able to sustain that. Whenever any information leaks, she will be the first suspect by the Russians.